POS0693 ULTRASOUND SHOWS ONGOING VESSEL WALL REMODELING IN GIANT CELL ARTERITIS FOR TWO YEARS AFTER DISCONTINUATION OF TOCILIZUMAB - FOLLOW-UP OF THE GUSTO TRIAL
Authors: L. Seitz, F. Lötscher, S. Reichenbach, P. Villiger, L. Christ
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The GUSTO (Giant cell arteritis (GCA) treatment with Ultra-Short glucocorticoids and TOcilizumab) trial evaluated the efficacy and safety of Tocilizumab (TCZ) monotherapy after a 3-day glucocorticoid-pulse in new-onset GCA [1]. Ultrasound measurements of the intima-media thickness (IMT) demonstrated a slow and steady decrease in the temporal arteries and a smaller and delayed effect on the axillary and subclavian arteries with TCZ monotherapy over 52 weeks [2]. Recently, a new Outcome Measures in Rheumatology (OMERACT) GCA ultrasonography score (OGUS) for monitoring disease activity in GCA has been proposed [3]. <h3>Objectives</h3> To investigate the evolution of the IMT after discontinuation of TCZ at week 52 in the GUSTO trial. Data up to week 156 are presented (two-year drug-free follow-up). <h3>Methods</h3> Eighteen patients with new-onset GCA were enrolled in the GUSTO trial. [1] Patients received 500 mg methylprednisolone intravenously for 3 consecutive days. Thereafter, glucocorticoid treatment was discontinued and TCZ (8 mg/kg bodyweight) was administered intravenously, followed by weekly subcutaneous TCZ injections (162 mg) from day 10 until week 52. Patients in clinical remission stopped TCZ at week 52 and entered the follow-up study. The maximum IMT of the temporal arteries (common superficial temporal artery, parietal and frontal branch) and IMT at landmarks of the axillary and subclavian arteries were measured bilaterally at weeks 52, 78, 104 and 156. The OGUS is calculated as follows: IMT divided by the rounded cut-off values of IMTs for each segment; the sum of these values is then divided by the number of segments available (maximum of 8 segments; axillary and temporal arteries considered). [3] <h3>Results</h3> At week 52, 13/18 patients were in relapse-free remission and entered the follow-up study. 1/13 patients presented with a minor relapse during the 104 weeks follow-up period. At week 156, 12/13 patients were in relapse-free and drug-free remission. The OGUS showed a steady decline with mean values of 0.90 (standard deviation (SD) 0.19) at week 52, 0.87 (SD 0.16) at week 78, 0.84 (SD 0.15) at week 104, and 0.79 (SD 0.12) at week 156. IMT measurements of one patient after restarting TCZ therapy were excluded (weeks 104 and 156). <h3>Conclusion</h3> After 52 weeks of treatment with TCZ, the IMT in GCA continues to decline during a drug-free period of up to or possibly more than two years. It can take more than one year after treatment discontinuation for the OGUS to become smaller than 1, indicating an average IMT below the rounded diagnostic cut-off values. Our results suggest a long-lasting remodeling phase of the vessel wall after treatment discontinuation. <h3>References</h3> [1]Christ, et al. Lancet Rheumatol, 2021 [2]Seitz, et al. Rheumatology, 2021 [3]Dejaco, et al. Ann Rheum Dis 2022 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Luca Seitz: None declared, Fabian Lötscher: None declared, Stephan Reichenbach: None declared, Peter Villiger Speakers bureau: Roche, MSD, Abbvie, Pfizer, Novartis, Grünenthal, Celgene, Sanofi, Chugai, Consultant of: Roche, MSD, Abbvie, Pfizer, Novartis, Celgene, Sanofi, Bristol-Meyers-Squibb(BMS), Grant/research support from: Roche, MSD, Abbvie, Lisa Christ Shareholder of: Gilead Sciences and F. Hoffmann-La Roche Ltd, Consultant of: Bristol-Myers Squibb and Novartis, Grant/research support from: Gilead Sciences, F. Hoffmann-La Roche Ltd, and Pfizer.